Turbocharger Posted September 27, 2005 Share Posted September 27, 2005 I've bought a transfer box off that lovely FridgeFreezer chap (on a windswept evening at the gates to Sodbury, no less) and this weekend is nominated for fitting. John gave me a T-box and a gear-with-2-bearings which I think is all the parts I need. Who's done this job before and what should I know beforehand? So far I think I have to get some long 10mm bolts with the heads cut off (thanks Mark90) and the gear needs fiddling to make it slide in easily because it's a 1.2 Discovery box. Anything else? Once I take it apart I'm kinda committed to reassembly without help... JB Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 27, 2005 Share Posted September 27, 2005 JB, Yeah just some long studs to guide to box on ........... also make sure you get the right bolts in the right holes...... especiallly the short one .......... coz if you put a long one in there you will crack the LT77 gearbox casing . Some boxes have a stud in this hole, but not all. Best to remove the H/brake drum etc to reduce the weight. Also check the diff lock switch adjustment / operation before you fit, coz they are a ba5tard to get at afterwards . Is this going to be the moment when you find that the gearbox mainshaft plines are knackered ? Also dont forget to replace the input shaft oil seal. I will also be fitting an Ashcroft replacement T/box this weekend, its the only bit I never replaced when I did the rebuild 30K ago ....... however, I am replacing the 1.222 with a standard 1.410, because even with the V8 and the best part of 200 ponies 1.222 gearing even on 235/85,s is too tall at 28mph/1000rpm. 5th becomes overdrive .......... 70mph at 2400rpm ......... just about OK on the motorway but a pain on fast hilly A roads .......... Ian Quote Link to comment Share on other sites More sharing options...
white90 Posted September 28, 2005 Share Posted September 28, 2005 we left all the floor panels in when we did mine, just removed he gear/transfer stick gaiters and the panels under the drivers seat and middle seat. the front seal on the transfer box is prone to leaking a tip is to add a bead of RTV around its face before bolting it onto the gearbox. with the handbrake off the weight is manageable with two and a trolley jack. Quote Link to comment Share on other sites More sharing options...
Bush65 Posted September 28, 2005 Share Posted September 28, 2005 There are 2 dowel pins for locating the transfer case. It is not possible to predict whether either dowel pin will remain with the gearbox case or the transfer case. So make sure that you have one and only one dowel in both positions before you install the replacement t/case. If you try to install the case with 2 pins butting together, it will be difficult to get the joint faces together. If you are missing either dowel pin you could get premature seal or gear failure. Make sure the mainshaft input gear has the cross-drilled lubrication hole for the splines. From what you said, it sounds like the mainshaft input gear may not be the one that was previously installed in the t/case. So you should check the bearing preload. The shims for adjusting the preload are behind the bearing cup (outer race) in the rear bearing housing. Some t/cases use a gasket in the joint for the rear bearing housing - later t/cases use sealant. If you fit the gasket to a later t/case or leave it out of an early t/case, the bearing pre-load will be affected. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted September 28, 2005 Author Share Posted September 28, 2005 Thanks for the tips re dowels and difflock linkage. I might have to rethink the 1.2 ratio eventually but we'll see. The handbrake drum and floor panels are coming out for easier access. 2 questions spring to mind: Input seal - where does it go? Does anyone have a part number or a drawing? Bearing preload - again, does anyone have a drawing? I'm sure it'll all make more sense when I've taken it apart but by then it might be too late... Quote Link to comment Share on other sites More sharing options...
white90 Posted September 28, 2005 Share Posted September 28, 2005 input seal front face of transfer box that mates to the gearbox. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted September 28, 2005 Author Share Posted September 28, 2005 Also dont forget to replace the input shaft oil seal. Tony - are you talking about this seal? I'm happy with a blob of RTV around the aluminium castings but I think Ian's referring to the seal that stops ATF from the R380 filling the transfer box... I think Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 29, 2005 Share Posted September 29, 2005 There’s a small oil seal that presses into the t/box housing – the G/box main shaft passes through it & into the T/box input gear. So yes, in essence it to stop ATF getting into the T/box, but in practice no ATF gets into the T/box and no EP90 gets into the G/box …. it just pi55es out the joint between the two . So, as Tony says, smear the T/box mating face with either RTV / or Hylomar as an additional seal. This will also help if the intermediate shaft 'O' fails due to wear in the T/box casing which is a very common fault (like mine). Ian Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 2, 2005 Author Share Posted October 2, 2005 Thanks to all for your help - TroddenMasses and I fitted it today (and yesterday ... how long should it take?) and I'm quite pleased with the 1.2 ratio - seems well mannered on the road. 5th is only for use on the flat now but it always seemed silly being able to pull away in 2nd and use 4th on roundabouts. It's certainly much quieter when cruising at speed although Vmax has fallen to around 85mph. Fuel consumption guesstimates will follow (as will the healing of my cuts, bruised knuckles, aching back etc). Special thanks to Keir and Lucy for putting me up for the night while my car dripped oil onto their drive. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 3, 2005 Share Posted October 3, 2005 TC, The new shiny Ashcroft T/box arrived on Friday B) and I fitted it on Saturday. The job was done & dusted in 5 hours ……… and that includes a small problem with the handbrake bracket as the existing was from an early classic RR and the rear housing of the defender T/box is very slightly different ….. so a little fabrication was required. The difference is most marked, gone is the light throttle gear whine (probably bearings as well) that would have put most cats and choirs to shame, gone is the loud occasional clunk from the centre diff due to excessive back lash. The major oil leak was indeed from where I had suspected …. the intermediate shaft had worn the housing. For what its worth, don’t expect a large change in fuel consumption with the 1.22 …….. I did a number of tests by driving the same A road 287 mile journey in mostly 5th and then mostly 4th …….. 4th being a bit shorter geared than a 1.410 in 5th. The V8 the fuel consumption was much the same. Remember the engine is working a lot harder with the taller gearing. Folk that have the GKN overdrive report that fuel remains unchanged they just get quieter driving on the m/way Like you when I first fitted the taller gears I was pleased, but with me I found the continual 5th / 4th change on fast A roads (like the 303) became a pain, but I did give it a 34K test . How were the G/box main splines ? Mine were OK as I had fitted a X drilled input gear when I rebuilt it all 34K ago. Ian Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 3, 2005 Share Posted October 3, 2005 a small problem with the handbrake bracket as the existing was from an early classic RR and the rear housing of the defender T/box is very slightly different I have found that same problem when I came to fit a defender handbrake to a RR transfer box, casting is the same but with different holes tapped for the different handbrake cable brackets. Just fitted the RR bracket in the end. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 3, 2005 Author Share Posted October 3, 2005 Ian - as you say, it's quieter but I'm not expecting a fuel consumption improvement. TBH as I work 15mins walk away from home it's more of a toy so economy isn't as important any more. I'll just keep an eye because I'm the geeky sort. The new box had a Disco handbrake assy but the late Ninety one (cable operated rather than the rod type?) bolted straight on. I may swap the xfr box back in 12 months if I don't like 1.2 and I can resolve the selector problem on the old box. Given that it's pretty worthless if not in working condition, it won't cost me anything to pull it apart and see what's wrong - there's no major whining or backlash, just a very sloppy selector somewhere inside I think. The splines are good - John supplied a brand new (but not cross-drilled) gear with the box, but when I took the old one out it was drilled and the splines were pristine so I refitted it. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 7, 2005 Author Share Posted October 7, 2005 As a further followup, I'm very pleased indeed with my new ratio after today's motorway thrash. It really seemed to have slowed the car down - it runs out of puff about 85mph - but then I realised I'm (passing everything on the motorway and) running a Disco speedo drive gear, as if I had 205R16 tyres on - I reckon that's about 10% low on the speedo? Meanwhile, cruising at an indicated 65mph is much more relaxed, the noise level's much lower and although it's blunted the edge of the performance I'm not changing down for motorway hills and the whole thing seems much more mechanically sympathetic. Fuel consumption is largely similar from what I can tell, maybe +/- 5%. Overall, very pleased. John (EGT peak is now 735°C - oops!) Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 7, 2005 Share Posted October 7, 2005 John, Yes, I found the motorway cruising to be OK with the taller gearing with rarely having to change down a cog ……… however, I found the fast A roads a totally different story, but then again the V8 lump has totally different characteristics to the 300tdi so maybe that has something more to do with it . Like you I am really pleased by dropping to the shorter gearing …….. for me it’s a more relaxed style of driving …… and keeps the V8 in the right rev range . My fuel consumption certainly seems no worse . Ian Quote Link to comment Share on other sites More sharing options...
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